Bulb locking mechanism



. g- 5, 1969 H. J. ZURSTADT 3,459,044

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United States Patent 3,459,044 BULB LOCKING MECHANISM Herbert J.Zurstadt, 1231 Berkshire, Grosse Pointe Park, Mich. 48236 Filed Mar. 1,1967, Ser. No. 619,839 Int. Cl. G01k 5/02 US. Cl. 73-368 5 ClaimsABSTRACT OF THE DISCLOSURE A remote thermometer having a charged bulbdisposed within a well. The well is provided to isolate the fluid systemunder test from the ambient atmosphere. The well is projected into alarge steam pipe or liquid tank, and the thermal bulb may then beinserted into the well to sense the steam or liquid temperature. Thebulb can be removed or replaced at any time without disturbing the wellor otherwise allowing the steam to escape into the ambient atmosphere.

Summary The invention is directed to a bulb locking mechanism which isusable with various well sizes, which firmly retains the bulb in thermalengagement with the well end wall, which is easily installed in andremoved from the well, and which is manufacturable at relatively lowcost.

The drawings FIG. 1 is a longitudinal sectional view of a bulb-wellassembly having one embodiment of the invention incorporated therewith.The assembly is shown in association with a remotely-located read-outmeans containing a pressure-responsive diaphragm, bellows, etc.

FIG. 2 is an enlarged side elevational view of a clamping element usablein the FIG. 1 apparatus.

The drawings in greater detail FIGURE 1 shows a vessel or passage wallwhich may in actual practice be a large steam pipe, refrigeration line,refrigeration tank, brine tank, or other container for a liquid orgaseous media 12 of temperature changing characteristics. Thetemperature may for example range from -40 F. to +180 F. or from 400 F.to 1200 F., depending on the particular installation. Wall 16 is shownwith an opening 14 therethrough for accommodating a well 16 used tocontain a thermal bulb 18, formed for example of stainless steel. Bulb18 is provided with a closed end wall 20 and a tubular side wall 22which telescopes over a plug-like adapter 24, a suitable heliarc weldbeing employed to secure the bulb and adapter together.

Aflixed to the reduced end portion of adapter 24 is a tubular sleeve 26which forms part of a fluid conduit means designated generally bynumeral 28. Sleeve 26 has an enlarged diameter at its opposite ends anda reduced diameter in its mid-portion, the reduced diameter portionextending for a considerable distance, as for example 12 or more inches.Sleeve 26 forms what is sometimes termed a bendable extension, itselongated length enabling it to be bent or curved at right angles atdifferent selected points therealong, depending on the position of wall10 in relation to the outer panel or surface behind which wall 10 islocated.

Extending within sleeve 26 is a filler tube 30 and a capillary tube 32,the filler tube being used to charge the bulb 18 to a suitable pressureor level with a suitable thermal charge, which may be a gas or volatileliquid, depending on the temperature range of media 12 and the desiredpressure change per unit tempera- 3,459,044 Patented Aug. 5, 1969 turechange. Capillary 32 extends through sleeve 26 into a conventionalflexible armor 32, said armor having a crimped and soldered connectionwith sleeve 28. The armor and shielded capillary tubing extend to acup-like gage housing 34 having a conventional diaphragm, bellows, orBourdon coil mounted therein to communicate with the capillary tubing.Armor 32 and the contained capillary tubing may be of various lengths,as for example 10 feet or feet, depending on the relative locations offluid vessel 10 and the control panel which mounts gage 34.

The general operation of the gage involves a thermal expansion of thebulb material which is transmitted through the capillary tubing to thediaphragm, bellows, or Bourdon coil 34, suitable mechanism beingprovided in the gage to translate movement of the diaphragm, etc. into avisible rotation of the temperature indicating pointer 36. As is wellknown, the same general system can be used to operate an electric switchor control valve in lieu of the illustrated gage 34.

The present invention is concerned particularly with mechanism forretaining bulb 18 in well 16. The illustrated retaining mechanismcomprises a nut 38 arranged to thread into a threaded opening in themouth portion 40 of the well when a turning pressure is applied on theWrench flats 42. Nut 38 is provided with an internal annular convergentcam surface 44 of frusto-conical character, and an internal threadedsurface designated generally by numeral 46. Cooperating with nut 38 isan annular clamping means configured to form an externally threadedsection 48, a wrench flat section 50, and a frustoconical cam surface52.

As shown best in FIG. 2, the clamping element is provided with adiametrical slot 54 extending for a considerable portion of the clampingelement length to form two deflectable sections 56 and 58. Internallythe clamping element is provided with a cylindrical surface 60 extendingfrom the left end of the element about twothirds of the way toward theright end of the element. Second smaller diameter cylindrical internalsurfaces 62 are formed in the rightmost portions of the clampingelement, the normal clearance between surfaces 62 and the outer surfaceof sleeve 26 being on the order of a few thousandths of an inch,sufficient to permit the clamping element to slide freely along thesurfaces of sleeve 26 when said element is disengaged from nut 38.

Assuming that bulb 18 has been inserted into well 16 so that its endwall 20 is in firm thermal engagement with end wall 21 of the well, theclamping element 47 can be threaded into nut 38, whereupon the camsurfaces 52 ride along the cam surface 44. During such movement the twodeflectable sections 56 and 58 of element 47 are forced inwardly so thatsurface portions 62 firmly grip on sleeve 26, thus retaining the bulbwithin well 16.

The drawing shows a single well 16 of a given length. However, inpractice the well length may vary depending on the nature of vessel 10,and the desired length of insertion of the bulb into media 12. The welllength penetration (dimension 13) may for example vary from about 5inches to about 8 inches, depending on the installation. The illustratedlocking means formed by nut 38 and clamping element 47 is adapted forretention of the bulb in firm thermal engagement with end wall 21irrespective of the well length. Thus, a given length bulb may beinserted into an 8 inch well or a 5 inch well, and the same clampingmechanisms 47 and 38 used to lock the bulb in place. The clamping isoperative for lock purposes at any point along sleeve 26 so that nospacers or other positioning devices are needed to assure correctlocking action with different length wells or bulbs.

It will be noted that slot 54 forms a path for flow of fluid between thespace within well 1 6 and the ambient atmosphere. Thus, referring toFIG. 2, fluid located rightwardly of clamping element 47 can flowthrough slot 54 into the large interior chamber defined by surface 60,and thence into the space located leftwardly of element 47. In somecases this fluid flow path can be advantageously used to safely ventfluid from the well interior, For example, should the well develop aleak the venting path can release dangerous pressure build-ups whichwould otherwise be released onto the repairmans face. Sometimes water orother liquid is poured into the space between the well interior surfaceand bulb outer surface to improve heat transfer; in conventionalarrangements the water when heated is apt to build up a pressure whichcan scald the serviceman while the bulb is removed from the well. Withthe vented arrangement it is of course not feasible to use a nonviscousliquid heat transfer medium between the well and bulb; instead a metalsleeve, viscous liquid, paste, copper wool, steel wool, etc. must beemployed for such purposes.

Variations in arrangement, contour of parts, etc. can of course be.

It is claimed:

1. In combination: a mounting well for a thermal bulb; said well havinga tubular side wall, an end wall, and an open mouth remote from the endwall; a temperature responsive power unit comprising a thermal bulbinsertable through the open mouth into said well, and fluid conduitmeans extending from the bulb through the mouth; and means for retainingthe bulb in the well, said retaining means comprising seat means formingan internal convergent cam surface and a threaded surface at the wellmouth, and deformable clamping means movable along the cam surface toexert a clamping pressure on the fluid conduit means; said deformableclamping means comprising an annular clamping element having a threadedsection meshable with the threaded surface on the seat means, and afrusto-conical section engageable with the cam surface; said annularclamping element being split for a portion of its length to provide atleast two spaced defiectable sections hingedly movable toward the fluidconduit means as the clamping element is threaded into the threadedsurface on the seat means.

2. The combination of claim 1 wherein the seat means is formed by anannular nut screwable into the well mouth; said nut having an innerdiameter at least as great as the outer diameter of the bulb to permitsaid bulb to pass therethrough.

3. The combination of claim 2 wherein the fluid conduit means comprisesan outer armor-forming sleeve and an inner capillary tubing.

4. The combination of claim 2 wherein the nut is formed with a passagetherethrough for venting of pressures from the space within the wellexternally of the bulb.

5. The combination of claim 2 wherein the annular clamping element isprovided with wrench flats located externally of the seat means wherebya wrench can be applied to the wrench flats to turn and advance theclamping element into the seat means; the inner diameter of said annularelement being substantially larger than the outer diameter of the fluidconduit means except in those areas where the defiectable sections areadapted to clamp onto the conduit means; said annular element beingsplit along its frustro-conical section and also along its threadedsection whereby the defiectable sections are elongated in the axialdirection.

References Cited UNITED STATES PATENTS 2,135,078 11/1938 Hubbard et a1.73-368 XR LOUIS R. PRINCE, Primary Examiner W. A. HENRY II, AssistantExaminer

